The prior art related to chucks includes the device shown in U.S. Pat. No. 3,970,323. In this patent the compression spring of the tightening device rests, on the one hand, against the body of the chuck and, on the other hand, against the intermediate ring, and the clamping sleeve is locked via a toothing and a pawl locking member on the intermediate ring in the direction against the direction of clamping rotation with respect to the intermediate ring. Accordingly in this case, the force of the compression spring is transmitted directly via the intermediate ring to the clamping sleeve, which has the disadvantage that for the cocking of the compression spring which acts in the direction of rotation, the gripping sleeve of the tightening device must be actuated in the same direction of rotation as that in which the chuck body turns relative to the clamping sleeve for the clamping of the clamping jaws. In the known chuck, by the holding fast of the clamping sleeve, the clamping jaws can first of all be brought into their clamping position until resting against the tool in question, whereupon the clamping sleeve turns in one's hand or the drive motor is stopped. In this way, there is not yet commenced the tightening effect with the following disadvantageous results in operation: the clamping jaws act on the tool shank in question in addition with the force of the compression spring in order to prevent automatic loosening of the clamping jaws particularly in the case of vibrations. For the activating of the tightening effect, in the case of the known chuck, while the gripping sleeve is held fast, the clamping sleeve must be turned further in the clamping direction of rotation of the body of the chuck, and it is thus not possible, via the rotary drive of the chuck body by which the clamping jaws can be brought into their clamping position, in addition to also actuate the tightening device.
Conversely, a loosening of the tightening device cannot be affected via the motor drive of the chuck body. For loosening in the case of the known chuck, the gripping sleeve must be turned in the direction of rotation of the opening of the chuck body and only then is the opening of the clamping jaws possible by holding the clamping sleeve and causing rotation of the chuck body in the direction of rotation in which the gripping sleeve had to be previously turned. The decisive factor for the disadvantage described is, therefore, that the relative rotation between the chuck body and the gripping sleeve is not able to effect the clamping of the clamping jaws as well as the following actuation of the tightening device. Conversely, the deactuation of the tightening device and the loosening of the clamping jaws in each case in the same direction of relative rotation is not possible.